Hi,
I wouldn't call it sketchy -- it sounds like something that could happen to anyone. When one has little to no free time, dream projects can kind of turn into some day projects to never gonna happen projects. Plus taking the time to haul it all the way down to a swap and such, he probably just wanted to get rid of it. Was there no power outlet around? I think those amps have an HV switch for the meter which I guess would have shown if the transformer was OK or not. I imagine he could even have been talked down a bit in price.
But an amp like that would have to be considered a project anyway right? Many things to check out, cleaning to be done, recommended upgrades and replacements to be done. I like doing things like that, but don't have an interest in high power at the moment so I would have passed. But it seems like a fun project to do!
73, Mark